PostgreSQL 19 Introduces Multi-Block Buffered Reads to Cut I/O Overhead

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PostgreSQL has traditionally fetched data one 8 KB page at a time, generating numerous small I/O operations that are inefficient for large sequential scans. PostgreSQL 19, currently in beta, introduces a new read stream layer that groups adjacent blocks into larger combined I/O requests, governed by the io_combine_limit parameter. The release also adds Asynchronous I/O (AIO) support, allowing the database to pipeline read requests without waiting for each one to complete, using methods such as worker threads or io_uring on Linux. Together, these changes reduce system call overhead and explicit prefetching replaces reliance on implicit OS readahead. Developers can measure the impact of these improvements using the EXPLAIN (ANALYZE, IO) command, which exposes detailed I/O statistics.

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How to Identify and Handle reCAPTCHA v2, v3, and Enterprise Variants

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ProgrammingDEV Community ·

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ProgrammingDEV Community ·

Afriex SDK Enables Developers to Build Full Cross-Border Remittance Apps

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